FIG. 11 is computer-image plan rendition of a photomicrograph of a wafer 10 as a result of laser scribing according to known technique. A top surface 2 of the wafer 10 has been altered by multiple scribing passes 3, 4, 5, and 6 that are depicted with black directional arrows to indicate translational scribing motion across the top surface 2. These multiple scribing passes have formed an intersection 7 where scribing has been concentrated as illustrated by a different surface texture at the intersection.
FIG. 12 is a computer-image perspective rendition of a photomicrograph of a die 12 after laser scribing and singulating according to known technique. The die 12 includes a top surface 13 and other structures that have been altered by multiple scribing passes 14 and 15 that are depicted with black directional arrows to indicate translational scribing motion. A cleavage plane 16 is indicated with a white arrow, as well as the bulk 17 of the die therebeneath. The top surface also shows a cutting onset margin 18. Where multiple scribing passes were carried out at what was an intersection, repeated laser scribing has resulted in a deep hole 19 due to the laser repeatedly passing through the intersection.
A consequence of the deep hole 19 and other cutting irregularities that can occur at an intersection is cracks, fissures, or other weaknesses are initiated in the bulk 17 of the die 12. When the die 12 is mounted such as on an epoxy base, thermal mismatch between the die 12 and the epoxy base can make the initiated weaknesses progress to die failure.